Understanding Amblyopia

When the doctor sees nothing and the patient sees nothing,

the diagnosis is αµβλυωπια.

- Hippocrates, 450 BCE

AMBLYOPIA: DEFINITION

•  Abnormal visual development •  Decreased best-corrected visual acuity •  Unilateral or bilateral •  Apparently normal physical exam, but may

also result from recognizable structural abnormalities

Understanding Amblyopia

AMBLYOPIA: SIGNIFICANCE

•  2%–4% of U.S. population affected •  Commonly unilateral •  Bilateral amblyopia (rare) may mean

permanently decreased visual acuity

Understanding Amblyopia

SCREENING: IMPORTANCE

•  Amblyopia is usually preventable or treatable

•  Early detection is key to effective treatment •  Life-threatening disorders may present as

amblyopia •  Screening responsibility rests with primary

care physician

Understanding Amblyopia

In most circumstances, amplyopia can be prevented

or treated.

Understanding Amblyopia

EARLY DETECTION: IMPORTANCE

•  Visual function develops early in life •  Treatment depends on plasticity of visual

system •  Treatment less likely to be effective as

children age

Understanding Amblyopia

Understanding Amblyopia

Decreased vision à retinoblastoma?

The ophthalmologist treats amblyopia,

but the primary care physician detects amblyopia.

Understanding Amblyopia

PREVENTING AMBLYOPIA: CONSIDERATIONS

•  Predisposing factors •  Presenting features •  Detection methods •  Treatment rationale

Preventing Amblyopia

AMBLYOPIA: PREDISPOSING FACTORS

•  Poor clarity (media opacities) or blockage of light pathway (ptosis)

•  Poor focus (refractive error) •  Poor aim (strabismus)

Preventing Amblyopia

Preventing Amblyopia

Poor clarity

Preventing Amblyopia

Poor focus one eye

Preventing Amblyopia

Poor focus both eyes

Preventing Amblyopia

Poor aim: strabismus

UNILATERAL AMBLYOPIA: PRESENTATION

•  Failed vision test •  Strabismus •  Parental concern •  Family history of amblyopia or strabismus

Preventing Amblyopia

May peek around occluder Adhesive patch works best

Preventing Amblyopia VISION SCREENING AGES 3-5

Preventing Amblyopia

Strabismus is the most common underlying cause of amblyopia.

DIPLOPIA IN CHILDREN

•  Not a feature of strabismus •  May indicate a serious condition •  Evaluate promptly and refer

Preventing Amblyopia

Leukocoria Enlarged cornea

PARENTAL CONCERNS

Preventing Amblyopia

A positive family history is often present in children with amblyopia.

Preventing Amblyopia

Preventing Amblyopia

Bilateral amblyopia

AMBLYOPIA: EARLY DETECTION

•  Assess red reflex •  Determine visual acuity •  Evaluate ocular alignment

Preventing Amblyopia

Preventing Amblyopia

Normal red reflex

Preventing Amblyopia

Assymetric red reflex

Preventing Amblyopia

Direct ophthalmoscope

Preventing Amblyopia

Direct ophthalmoscope: assessing red reflex

Preventing Amblyopia

Direct ophthalmoscope: examining retina

Preventing Amblyopia

Can your child see?

NORMAL INFANT VISION

•  Good visual function •  Fixate and follow with each eye •  Steady fixation

Preventing Amblyopia

Testing infant vision: Can your child see?

Preventing Amblyopia

Suspected poor vision: test response to bright light

Preventing Amblyopia

Preventing Amblyopia

Testing infant vision: Preferential looking test

Preventing Amblyopia

Measuring visual acuity at 18 months to 3 years: picture chart

Preventing Amblyopia

Picture chart Single E chart

Preventing Amblyopia

Snellen acuity chart

Preventing Amblyopia

Depth perception (stereopsis) testing

Preventing Amblyopia

Testing infant vision: Assessing corneal light reflex

Normal Esotropia

Preventing Amblyopia

Normal Exotropia

Preventing Amblyopia

Hypertropia Hypotropia

Preventing Amblyopia

Eyes appear aligned with head tilt and turn.

Misalignment revealed when head is straightened.

Preventing Amblyopia

REFERRAL: IMMEDIATE

•  Poor red reflex in one or both eyes •  Concern about visual function by parent or

doctor •  Asymmetric or diminishing visual acuity •  Constant or acute-onset strabismus

Preventing Amblyopia

REFERRAL: LESS EMERGENT

•  Intermittent strabismus on examination •  Persistent parental concern •  Associated syndromes or systemic

disease •  Reduced visual acuity in one or both eyes

Preventing Amblyopia

AMBLYOPIA: TREATMENT RATIONALE

•  Clearing the media •  Focusing the image •  Initiating amblyopia therapy

Preventing Amblyopia

Preventing Amblyopia

Congenital cataracts

Preventing Amblyopia

Congenital ptosis

Ophthalmologists can quantify refractive error in

infants. Children usually do well with

eyeglasses.

Preventing Amblyopia

•  Carefully supervise children wearing therapeutic contact lenses.

•  Retain a pair of backup eyeglasses.

Preventing Amblyopia

•  Improves visual acuity

•  Does not eliminate strabismus

Preventing Amblyopia OCCLUSION THERAPY:

PURPOSE

OCCLUSION THERAPY: PRECAUTIONS 1

•  Monitor visual acuity carefully at close intervals

•  Ensure vision is not being reduced in non-patched eye (“occlusion amblyopia”)

Preventing Amblyopia

•  Part-time occlusion may suffice

•  Ensure parents understand purpose of patching and importance of compliance

•  Follow child’s visual status into the teen years

Preventing Amblyopia OCCLUSION THERAPY:

PRECAUTIONS 2

Preventing Amblyopia

Skin irritation from patching can be avoided.

ATROPINE PENALIZATION THERAPY

•  Atropine ointment or drops in non-amblyopic eye at prescribed levels

•  Atropinized eye cannot accommodate for near vision

•  Child can still use better-seeing eye for distance

•  Child switches fixation at near to amblyopic eye

Preventing Amblyopia

•  Monitor VA carefully. •  Ensure near VA in

amblyopic eye can support near tasks

•  Allergic reactions are rare (<1%)

•  Systemic side effects are uncommon and minimal

Preventing Amblyopia ATROPINE THERAPY:

PRECAUTIONS

Warn parents that one eye will have a “fixed and dilated pupil.”

Preventing Amblyopia

Medieval “occlusion masks” to treat strabismus and amblyopia

AMBLYOPIA: PREDISPOSING FACTORS

•  Poor clarity of ocular media or light blockage

•  Poor focus •  Poor aim

Summary

AMBLYOPIA DETECTION

•  Assess red reflex •  Determine visual acuity •  Evaluate ocular alignment

Summary

AMBLYOPIA TREATMENT

•  Clearing the ocular media •  Focusing the image •  Amblyopia therapy •  Success requires communication among

parents, PCP, and ophthalmologist

Summary